From Dinosaurs To Mammoths

Ancient Life In Oklahoma

By Hugh Jones

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Editor's note: Several months ago, we examined the possibility of animals being in Heaven. Now, we explore evolution, without endorsing either viewpoint. The fact is, these animals existed, and they were here. How and when, you decide.

Step into our time machine. We're going back, way back, to different times and very different Oklahomas.

The PetGazette usually writes about animals in the present, but we were curious. What kind of animals used to live here? Of course, here wasn't always here. The state has done a lot of traveling, thanks to plate tectonics (continental drift). At one of our stops, we're under water; at another, we're tropical.

Our time machine is the Sam Noble Oklahoma Museum of Natural History at the University of Oklahoma in Norman. Our guide is Dr. Nick Czaplewski, staff curator in vertebrate paleontology. Paleontology tells us what was "back there" through the study of fossils (plant and animal remains).

"Where do you want to go," asks Czaplewski. "We'll have to back up tens of thousands of years, maybe millions to really see a difference."

Czaplewski sits behind a desk cluttered with papers and bones. When asked about the contents of several plastic containers, he leans forward, surveying them. "Oh, there's a rabbit, frog, mice, bear, camel."

Dr. Nick Czaplewski

Camel? At one time, Oklahoma looked more like Africa, with camels, mammoths (extinct elephants) and saber-toothed tigers roaming the grasslands. At another time, we resembled Steven Spielberg's movie Jurassic Park.

"What was here a million years ago is different from what was here at two million and so on," says Czaplewski. "The whole process is so complex and dynamic, always changing."

Stopping at 11,000 years, we'll see some of those Africa-type animals. It might be a bit cool though. The last ice age has just ended. The Pleistocene Epoch had a number of Ice Ages with glaciations lasting thousands of years, and long interglacial spells in between.

"Glaciers didn't reach this far, but they affected what happened here and everywhere: atmospheric and climate patterns, ocean circulation patterns and changes in sea level," says Czaplewski.

It also was a bad time for animals. A lot of the big mammals in North America became extinct. It could have been climate or humans, Czaplewski speculates.

Mammoth Skeleton

"That's about the time humans show up after crossing the land bridge between North America and Eurasia. The animals here didn't co-evolve with them like they did in Africa. Since the animals didn't recognize them, they didn't fear them. If you kill all the deer, mammoths, ground sloths, etc., there's nothing for saber-tooths to eat. What makes it through is largely up to chance."

In our time line, 11,000 years are a blink of the eyes. So let's back up to yesterday–two and a half million years–when North and South America got acquainted. Over the ages, North America has played bumper cars off and on with Asia and Europe. But South America was an isolated island continent for many millions of years. When the two came together through the Central America land bridge, it led to what's called the Great American Interchange.

Many animals went south, many came north. Some made it, some didn't. But that's where our armadillo, opossum and porcupine came from. Likewise, South America wouldn't have llamas if not for us.

"Each time a connection occurs, you share species of animals," Czaplewski explains. "And when there's a break and the ocean comes across, then the oceans share theirs. It adds to diversity. But the land bridge also acts as a filter. Not everything can cross, only those that can survive in it."

Oklahoma has been covered with water several times, the last in the Cretaceous Period–about a hundred million years ago, give or take a mil. We were also under water during parts of the Paleozoic Era. A lot happened in that era, from life exploding in the seas, to life colonizing the land, the land masses coming together into one supercontinent called Pangaea, mountain ranges (the Appalachians) rising.

The era gave us fossils like Trilobites (hard-shelled, crab-like creatures). Trilobites have been found in the Arbuckle Mountains in the south-central part of the state.

In the late Cretaceous, the seaway ran all the way from the Gulf of Mexico to the Arctic. Not much is found in the way of vertebrates (backbone, spinal column), because we weren't near a beach where deposition and burial of bones could take place. Common finds are ammonites, sea urchins, sand dollars–not very exciting, but it gets better.

"Why were we flooded? Plate tectonics," says Czaplewski, motioning with his hands and arms. "Our thin crust is driven by convection currents deep in the earth, pushing the continents around, warping up and down, causing the land over here to rise, while pushing the land over there down. The late Cretaceous is when the Rocky Mountain uplift began. They went up, we went down, the water flowed in. As they grew higher, they lifted us, draining the water."

So at one time, we were beachfront property with the sea located about where the Red River is. The rest of the state was open woodland. And during that time, along with other points in the Mesozoic Era, we were home to some very special inhabitants.

Pentaceratops

To find dinosaurs in Oklahoma, you have to go to extremes: the southeast corner (the beach) or far northwest in the Panhandle. Pack lunch, the trip will take a few million years. The dinosaurs in the southeast are from the Cretaceous, but the ones in the Panhandle are from Spielberg's place, the Jurassic. And what you'll find there is just amazing.

Two are on stunning display at the museum: the world's largest skeleton of an Apatosaurus (a.k.a. Brontosaurus). It's one of the sauropods (or long necks), and they were the biggest land animals that ever lived. This one is over 90 feet long and weighed 40 tons. Let that sink in–the length is that of a nine-story building's height. The weight is equivalent to about 26 cars! You could easily walk under him with plenty of clearance.

And you could walk under him without too much worry (other than getting squashed), because he was a plant eater. But poised beside him, ready to strike, is the giant predator Saurophaganax, the largest Jurassic carnivore. This one is 39 feet and 4-6 tons. "Carnivores are rare," says Czaplewski. "You find animals in the same proportion they existed–few from the top of the food chain, many of the herbivores they fed on. What was true then is true today. That's why you see more rabbits than coyotes. The more common they are, the better the chances of getting buried and fossilized."

There are several more dinosaurs we could detail, but gee, it's getting late–65 million years ago. Time to go, because we know something they don't. There's a menace hurtling toward them from outer space. Many scientists believe a huge meteorite impact wiped out the dinosaurs.

Just as surely as we are the dominate species today, dinosaurs ruled the world then. But scurrying around their feet were tiny rodent-like creatures, mammals. And they will escort us back to today.

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